This invention relates generally to a seal ring, and more particularly to a seal ring having a cone spring encapsulated within the seal ring.
Various seals have been developed for use in sealing a variable space between two relatively rotatable members. A joint in which movement of this type occurs is that found in the track structure of a track-type vehicle such as a tractor or the like. For example, U.S. Pat. No. 4,392,657, issued Jul. 12, 1983, to Robert D. Roley, titled Belleville Spring Loaded Seal and assigned to the assignee of the present invention, describes a seal structure having a Belleville spring which urges the sealing component of the structure having a Belleville spring which urges the sealing component of the structure into sealing engagement with an opposed face of the joint assembly. In the Roley seal structure, the Belleville spring is disposed within;the actual sealing element of the assembly and is modified by a plurality of annularly arranged openings extending through the spring itself. The sealing element, containing the Belleville spring, is attached to one end of a support spring which has an opposite end pressed into an annular groove formed in the radial wall of a counterbore in which the seal assembly is positioned. The seal assembly described by Roley requires a relatively deep counterbore to support the sealing element, which uses a cantilevered spring to support the Belleville spring, in addition to requiring a deep groove machined into the flat radial face of the counterbore to support the anchored end of the cantilevered spring.
The present invention is directed to overcoming the problems set forth above. It is desirable to have a seal ring in which a Belleville spring advantageously provides improved sealing performances a result of a cone, or Belleville, spring encased in the seal ring. The cone spring applies a consistent load to a sealing element of the seal ring. It is also desirable to have a seal assembly which only requires a relatively shallow counterbore, thereby allowing more engagement area between the member in which the counterbore is formed and a pin pressed into the bore of the member. It is also desirable to have such a seal assembly that does not require mounting by an annular cantilevered spring that must be retained within an additionally formed groove in the base of the counterbore.
The present invention is directed to a seal assembly having a unitary structure.
In accordance with one aspect of the present invention, an annular seal ring for sealing a joint between firsthand second members that are coaxially mounted on an elongated cylindrical member, are rotatably movable with respect to each other about a longitudinal axis of the elongated cylindrical member and have a variable space between axially opposed radial faces of the first and second members. A radial face of a preselected one of the first and second members has a counterbore defined by a cylindrical circumferential wall and a recessed radial wall extending radially inwardly from the cylindrical circumferential wall. The annular seal ring embodying the present invention is positionable within the counterbore and includes an annular body having a radially outer cylindrical wall adapted to be received, and positioned in forced abutment with, the cylindrical circumferential wall of the counterbore. The annular body also has a radially inner cylindrical wall, axially spaced apart front and rear surfaces, and an annular lip projecting outwardly from the front surface of the annular body. The annular seal ring also includes an annular frustoconical spring that is axially aligned with the annular lip disposed on the front surface of the body, and is completely encapsulated within the annular body at a position between the annular lip and the real surface of the body.
Another feature of the annular seal ring embodying the present invention includes the rear surface of the annular body having a seating surface extending outwardly from the rear surface at a position adjacent the radially outer cylindrical wall of the annular body for a distance sufficient to abut the recessed radial wall of the counterbore when the annular seal ring is assembled in the joint.
Yet another feature of the annular seal ring embodying the present invention includes the annular body having a thrust load-resisting surface extending axially outwardly from the rear surface of the annular body at a position adjacent the inner cylindrical wall of the annular body for a distance sufficient to abut the recessed radial wall of the counterbore when the annular seal ring is assembled in the joint.
Still other features of the annular seal ring embodying the present invention include the annular body being formed of a polymeric material, the annular body being formed of a material having a Shore D hardness from about 45 to about 55, and the annular frustoconical ring being insert molded in the annular body.